bitcoin_wire/hash256

A fixed-width hash value used throughout Bitcoin wire data.

Types

Hash256

opaque </>

A generic 256-bit hash value stored in Bitcoin wire order.

This name describes the value’s width, not the single-SHA-256 algorithm. Bitcoin serializes these hashes in little-endian byte order, which is the order this type stores and exposes through to_bytes_le.

pub opaque type Hash256

Hash256Error

</>

An error that occurred while constructing a Hash256.

pub type Hash256Error {
  InvalidBitCount(actual: Int, expected: Int)
}

Constructors

```
InvalidBitCount(actual: Int, expected: Int)
```
The input did not contain exactly 256 bits.

The fields contain the measured and required bit counts, respectively.

Values

from_bytes_le

</>

pub fn from_bytes_le(
  bytes: BitArray,
) -> Result(Hash256, Hash256Error)

Construct a Hash256 from exactly 32 little-endian bytes.

Returns an error if the supplied value does not contain exactly 256 bits. The bytes are stored verbatim without interpreting the hash’s semantic role.

Examples

from_bytes_le(<<0:size(256)>>)
// -> Ok(Hash256) representing an all-zero hash

from_bytes_le(<<1, 2, 3>>)
// -> Error(InvalidBitCount(actual: 24, expected: 256))

to_bytes_le

</>

pub fn to_bytes_le(hash: Hash256) -> BitArray

Return the raw little-endian byte representation of a hash.

The returned BitArray is always exactly 32 bytes long and uses the same byte order found in Bitcoin wire data.

to_display_hex

</>

pub fn to_display_hex(hash: Hash256) -> String

Format a hash using Bitcoin’s conventional lowercase display notation.

Bitcoin displays identifiers such as txids and block hashes with the wire-order bytes reversed. The returned string therefore contains exactly 64 lowercase hexadecimal characters.